Lubricant



Patented Aug. 15, 1939 oric LUBRICANT Clarence M. Loane, Whiting, andBernard H.

Shoemaker,

Hammond, Ind.,

assignors to Standard Oil Company, Chicago, 111., a corporation ofIndiana No Drawing. Application November 2, 1936,

Serial No. 108,833 g 1 17 Claims.

This invention relates to lubricants and, in particular, to additionagents imparting to lubricants improved properties.

Our invention has particular utilityin preventing and/or inhibiting thecorrosion of hard metal alloy bearings such as copper-lead, cadmium--nickel, and cadmium-silver bearings which, to a large extent, havereplaced soft metal bearings such as Babbitt metal in the trend towardinthe range of S. A. E. 10 oils, and which have been subjected to suchrefining processes such as, for

example, solvent extraction, that the paraffinicity of the oil ismarkedly increased. It has been found that highly refined lubricatingoils cause corrosion to alloy bearings of the cadmium-silver type to theextent of 5 mg/cmi and even greater when such bearings are submerged forhours or less in an air agitated oil which has been preoxidized at about340 F. for 25 to 50 hours. .The motor oils may be highly refinedlubricating oils as such or mixtures of highly refined lubricating oilswith less highly refined lubricating oils, or stated in another way,mixtures of corrosive oils and non-corrosive oils, examples of thelatter being lubricating oilfractions from Winkler crude or crudes ofthe Winkler type.

We have found that corrosion of hard metal alloy bearings can beinhibited and highly desirable properties can be imparted to thelubricating oil by adding thereto up to 2% but preferably 0.05% to 0.75%of certain organic materials, particularly the aliphatic and aromaticpoly thiocyanates and the aliphatic and aromatic poly isothiocyanateshaving the general formulas aromatic group and n is a wholenumbergreater than one.

Examples of the poly thiocyanates which we may use are:

Dithiocyano ethane Dithiocyano propane Dithiocyano butane Dithiocyanoheptane Trithiocyano heptane Dithiocyano octane Trithiocyano octaneDithiocyano dodecane 1,2,4 trithiocyano benzene Para phenylenedithiocyanate Ortho phenylene dithiocyanate Meta phenylene dithiocyanateExamples of the poly isothiocyanates which may be used are:

Di isothiocyano propane Di isothiocyano butane Di isothiocyano heptaneTri isothiocyano heptane Ocetene di isothiocyanate Tri isothiocyanooctane Dodecene di isothiocyanate 1,2,4 tri isothiocyano benzene Paraphenylene di isothiocyanate Ortho phenylene. di isothiocyanate Metaphenylene di isothiocyanate Our invention also contemplates the use ofthe polymers obtained by heating mustard oil with an aqueous solution ofpotassium acetate, or by heating mustard oil with dilute hydrochloricacid.

We have also found that certain metallo poly thiocyanates may be usedeffectively. Compounds: such as potassium ferri thiocyanate and ammoniumferri thiocyanate are examples of the type of metallo poly thiocyanateswe prefer to use. The metallo poly thiocyanates are best dissolved inthe oil by adding, for example, KSCN to a slightly acidified FeClasolution and extracting the aqueous solution with ether. The etherextract by blowing. Since these compounds impart color to the oil theyare preferably used where discoloration of the oil is not detrimental toits use.

Since these compounds are subjected to high temperature conditions it ishighly desirable that the compound of the aforementioned type havingboiling points of about 400 F. or greater be used. The eifectiveness ofcompounds of the above is then added to the oil and the ether removedtype as corrosion inhibitors is demonstrated by the following test inwhich they were subjected to a set of conditions, which is more severethan those encountered in the actual operation of internal combustionengines. The compounds were tested by the following method.

The weighed bearings are placed in a highly refined oil containing theinhibitor which is air agitated at about 341 F. At periodic intervalsthe bearings are removed from the oil bath, washed free of oil and theloss in weight determined. Each time before being replaced in the oilbath the bearings are polished bright and reweighed and again tested forpredetermined periods.

In the above test the oil used was a motor oil refined to such an extentthat a loss in weight of more than 5 mg. per cm. is obtained in 25 hoursor less on a cadmium-silver alloy bearing submerged in an air agitatedoil at 340 F., which oil has been preoxidized for 25-50 hours at about340 F.

Using the above described test the following results were obtained.

Periods on 1st 2nd 8rd 4th 5th 2,4 hrs. 6 hrs. 16 hrs. 0 hrs. 16 hrs.

Loss in rug/cm Control 3. 6 5. 0 20. 5 .2% ethylene dithiocyanate 0.90.0 2.9 11.0 2% dodecene dithiocyanate 0.0 0.0 0. 7 1. 3 2G. 5 .2%octene dithiocyanate 0. 1 0. 0 0.9 6.6 Mustard oil potassium acetatepolymer 0.0 0. 0 0.0 0. 0 0. 0 Mustard oil H01 powmer 0. 0 0. 0 0. 0 0.0 0. 0 3% QKSON-Fe (SCNh. 0.1 1.1 3.6 1.0 .2% 1(NH4SCN) Fe (SCNh... 0.51.2 2. 5 0.9

While we have described in detail the use of the hereinbefore mentionedcompounds as corrosion inhibitors in highly refined lubricating oils,our invention is not limited thereto, but contemplates the use of up to10% of these compounds in lubricating oils for the purpose of improvingthe film strength thereof, reduce engine wear and to impart tolubricants improved extreme pressure characteristics. These compoundsmay also be used to improve the lubricity and other properties oflubricating oils.

Some of the foregoing compounds may not be completely soluble in tirelubricant, in which case effective results are obtained by suspendingthe inhibitor in the lubricant by means of a small amount of a peptizingagent such as aluminum naphthenate, aluminum stearate, etc.

We do not limit ourselves to the specific embodiments of our inventionherein described except as defined by the appended claims.

We claim:

1. An improved extreme pressure lubricant comprising a minerallubricating oil and from about 0.05% to about 10% of an organic compoundhaving the general formula R(Y)n in which R is a substituent selectedfrom the group consisting of an aliphatic group, an aromatic group and ametal, Y is a radical selected from the group consisting of a thiocyanoradical and an isothiocyano radical and n is a whole number greater than1.

2. An improved extreme pressure lubricant comprising a minerallubricating oil and from about 0.05% to about 10% of a polythiocyanatehaving the general formula R(SCN) in which R is a. substituent selectedfrom the group consisting of an aliphatic group, an aromatic group anda'metal and n is a whole number greater than one.

3. An improved extreme pressure lubricant comprising a minerallubricating oil and from about 0.05% to about 10% of apolyisothiocyanate having the general formula RkNCSM in which R is asubstituent selected from "he group consisting of an aliphatic group, ana10- matic group and a metal and n is a whole number greater than one.

4. An improved extreme pressure' lubricant comprising minerallubricating oil and a polythiocyanate having the general formula RtSCN)n in which R. is an aliphatic group and n is a whole number greater than1, said aliphatic polythiocyanate being added in amounts suflicient toimpart extreme pressure properties to said lubricating oil.

5. An improved extreme pressure lubricz nt comprising a minerallubricating oil and from about 0.05% to about 10% dodec'enedithiocyanate.

6. An improved extreme pressure lubricant comprising a minerallubricating oil and from about 0.05% to about 10% octene dithiocyanate.

7. An improved extreme pressure lubricant comprising mineral lubricatingoil and a polythiocyanate having the general formula R(SCN)1. in whichR. is an aromatic group and 11. is a whole number greater than 1, saidaromatic polythiocyanate being added in amounts suflicient to impartextreme pressure properties to said lubricating oil.

8. An improved extreme pressure lubricant comprising a minerallubricating oil and an aliphatic polyisothiocyanate having the generalformula R(NCS)n in which R is an aliphatic group and n is a whole numbergreater than 1, said aliphatic polyisothiocyanate being added in amountssufficient to impart extreme pressure properties to said lubricatingoil.

9. An improved extreme pressure lubricant comprising a minerallubricating oil and an aromatic polyisothiocyanate having the generalformula RINGS)" in which R is an aromatic group and n is a whole numbergreater than 1, said aromatic polyisothiocyanate being added in amountssufficient to impart extreme pressure properties to' said lubricatingoil.

10. An improved extreme pressure lubricant comprising a minerallubricating oil and from about 0.05% to about'10% mustard oil potassiumacetate polymer.

11. The method of preventing the corrosion of bearing metal alloyshaving the corrosive susceptibility of alloys of the group consisting ofcadmium-silver, cadmium-nickel and copperlead alloys in the presence ofa highly refined lubricating oil in internal combustion engines whichcomprises adding to said lubricating oil a substantial amount but lessthan 2% of .an organic compound having the general formula RAY) in whichR is a substituent selected from the group consisting of an aliphaticgroup, an aromatic group and a metal, Y is a radical selected from thegroup consisting of a thiocyano radical and an isothiocyano radical andn is a whole number greater than 1.

12. The method of preventing the corrosion of bearing metal alloyshaving the corrosive susaiea'roo mula R(NCS)n in which R is ahydrocarbongroup selected from the group consisting oian aliphatic group and anaromatic group andn is a whole number greater than 1.

13. The method of preventing the corr,osion of bearing metal alloyshaving the corrosive susceptibility of alloys of the group consisting ofcadmium-silver alloys, cadmium-nickel alloys and copper-lead alloys inthe Wstlnceoiahigb 1y refined lubricating oil in internal conibustionengines which comprises adding ,to.said .lubri-' eating oil asubstantial amountbut less 'than 2% of a polythiocyanate having. the.geneialjiormula R(SCN)n in which R is ahyd'roca'rb'onselected from thegroup consisting of an aliphatic group and an aromatic group, and n is awhole number greater than one.

14. The method of preventing the corrosion of bearing metal alloyshaving the corrosive susceptibility of alloys of the group consisting ofcadmium-silver alloys, cadmium-nickel alloys and copper-lead alloys inthe presence otahigh- 1y refined lubricating oil in internal combustionengines which comprises adding to said lubrieating oil a. substantialamount, but less than 2%, of an aliphatic polythiocyanate having thegeneral formula R SCN n in which R is an allphatic group and 1z' is awhole number greater than 1.

15. The method of preventing the corrosion than 1.

of bearing metal alloys having the corrosive susceptibility of alloys ofthe group consisting of cadmium-silver alloys, cadmium-nickel alloys andcopper-lead alloys in the presence of a highly refined lubricating oilin internal combustion engines which comprlsesaddlng to said lubrieatingoil a submantial amount, but less than 2%; of an aromaticpolythiocyanate having the general formula RASON) in which R is anaromatic group and n is a whole number greater than 1.. 1 I

16. The method of preventing the corrosion of bearing metal alloyshaving the corrosive susceptibility of alloys of the group consisting of.cadmium-'silver alloys, cadmium-nickel alloys I andc'opper-lead alloysin the presence of a higha ly refined lubricating oil in internalcombustion engines which comprises adding to said lubricating oil asubstantial amount, but less than 2%, of an aliphatic polyisothioeyanatehaving the general formula R.(NCS) in which R is an aliphatic group andn is a whole number greater than 1.

17. The method oi preventing the corrosion oi bearing metal alloyshaving the corrosive sus-v ceptibility of alloys of the group consistingof cadmium-silver alloys, cadmium-nickel alloys and copper-lead alloysin the presence of a highly refined lubricating oil in internalcombustion engines which comprises "adding to said lubricating oil asubstantial amount, but less than 2%, of an aromatic polyisothiocyanatehaving the general formula R(NCS) in which R is an aromatic group and nis a whole number greater

